Question

我想从以下网站获取一些数据：

http://wttv.click-tt.de/cgi-bin/WebObjects/nuLigaTTDE.woa/wa/teamPortrait?teamtable=1673669&pageState=rueckrunde&championship=SK+Bez.+BB+13%2F14&group=204559#

该网站包含一些有关乒乓球的数据。只有登录才能在上一季不登录的情况下访问实际季节。对于实际的季节，我已经创建了一些代码来获取数据并且它工作正常。我正在使用HtmlAgilityPack中的HttpClient。代码如下所示：

            HttpClient http = new HttpClient();
            var response = await http.GetByteArrayAsync(website);
            String source = Encoding.GetEncoding("utf-8").GetString(response, 0, response.Length - 1);
            source = WebUtility.HtmlDecode(source);
            HtmlDocument resultat = new HtmlDocument();
            resultat.LoadHtml(source);

            Do something to get the relevant data from resultat by scanning the DocumentNodes from resultat...

现在我想从需要登录的网站上获取数据。有没有人知道如何登录网站并获取数据？必须通过单击“Ergebnishistorie freischalten ...”然后输入用户名和密码来完成登录。

Answer 1

执行网站登录的方法有很多种，具体取决于特定网站使用的身份验证方法（表单身份验证，基本身份验证，Windows身份验证等）。通常网站使用FormsAuthentication。

要使用HttpClient在标准FormsAuthentication网站上执行登录，您需要设置CookieContainer，因为将在Cookie上设置身份验证数据。

在您的具体示例中，登录表单对HTTPS中的任何页面进行POST，我使用https://wttv.click-tt.de/cgi-bin/WebObjects/nuLigaTTDE.woa/wa/teamPortrait?teamtable=1673669&pageState=rueckrunde&championship=SK+Bez.+BB+13%2F14&group=204559作为示例。这是使用HttpClient发出请求的代码：

var baseAddress = new Uri("https://wttv.click-tt.de/");
var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { CookieContainer = cookieContainer })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
    //usually i make a standard request without authentication, eg: to the home page.
    //by doing this request you store some initial cookie values, that might be used in the subsequent login request and checked by the server
    var homePageResult = client.GetAsync("/");
    homePageResult.Result.EnsureSuccessStatusCode();

    var content = new FormUrlEncodedContent(new[]
    {
        //the name of the form values must be the name of <input /> tags of the login form, in this case the tag is <input type="text" name="username">
        new KeyValuePair<string, string>("username", "username"),
        new KeyValuePair<string, string>("password", "password"),
    });
    var loginResult = client.PostAsync("/cgi-bin/WebObjects/nuLigaTTDE.woa/wa/teamPortrait?teamtable=1673669&pageState=rueckrunde&championship=SK+Bez.+BB+13%2F14&group=204559", content).Result;
    loginResult.EnsureSuccessStatusCode();

    //make the subsequent web requests using the same HttpClient object
}

然而，许多网站使用一些javascript加载的表单值或甚至更多的一些验证码控件，显然这个解决方案将无法正常工作。这可以像使用WebBrowser控件那样完成（通过在表单字段上自动输入用户输入然后点击登录按钮，此链接有一个示例：https://social.msdn.microsoft.com/Forums/vstudio/en-US/0b77ca8c-48ce-4fa8-9367-c7491aa359b0/yahoo-login-via-systemnetsockets-namespace?forum=vbgeneral）。

作为一般规则检查登陆您所需网站的方式，请使用Fiddler：http://www.telerik.com/fiddler：当您点击网站上的登录按钮时，请观看Fiddler并找到登录请求（通常是第一次请求）在您单击“登录”按钮后，通常是POST请求。）

然后检查请求数据（选择请求并转到“检查器” - “TextView”选项卡）并尝试在代码上复制请求。

在左侧窗格中，Fiddler拦截了所有请求，右侧窗格中有请求和响应检查员（顶部有请求检查员，底部有响应检查员）

修改

与旧WebRequest类相同的代码：http://rextester.com/LLP86817

var cookieContainer = new CookieContainer();

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("https://wttv.click-tt.de/");
request.CookieContainer = cookieContainer;
//set the user agent and accept header values, to simulate a real web browser
request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36";
request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";


//SET AUTOMATIC DECOMPRESSION
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;

Console.WriteLine("FIRST RESPONSE");
Console.WriteLine();
using (WebResponse response = request.GetResponse())
{
    using (StreamReader sr = new StreamReader(response.GetResponseStream()))
    {
        Console.WriteLine(sr.ReadToEnd());
    }
}

request = (HttpWebRequest)HttpWebRequest.Create("https://wttv.click-tt.de/cgi-bin/WebObjects/nuLigaTTDE.woa/wa/teamPortrait?teamtable=1673669&pageState=rueckrunde&championship=SK+Bez.+BB+13%2F14&group=204559");
//set the cookie container object
request.CookieContainer = cookieContainer;
request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36";
request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";

//set method POST and content type application/x-www-form-urlencoded
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";

//SET AUTOMATIC DECOMPRESSION
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;

//insert your username and password
string data = string.Format("username={0}&password={1}", "username", "password");
byte[] bytes = System.Text.Encoding.UTF8.GetBytes(data);

request.ContentLength = bytes.Length;

using (Stream dataStream = request.GetRequestStream())
{
    dataStream.Write(bytes, 0, bytes.Length);
    dataStream.Close();
}

Console.WriteLine("LOGIN RESPONSE");
Console.WriteLine();
using (WebResponse response = request.GetResponse())
{
    using (StreamReader sr = new StreamReader(response.GetResponseStream()))
    {
        Console.WriteLine(sr.ReadToEnd());
    }
}

//request = (HttpWebRequest)HttpWebRequest.Create("INTERNAL PROTECTED PAGE ADDRESS");
//After a successful login, you must use the same cookie container for all request
//request.CookieContainer = cookieContainer;

//....

HttpClient通过登录c＃从网站上抓取数据

1 个答案:

修改